Estrogens, estradiol receptors and peroxidase activity in human mammary carcinomas

Estrogens, cytoplasmic estradiol receptors, nuclear estradiol receptors and peroxidase activity were measured in human breast carcinomas. No correlation was found between either estrogens, cytoplasmic estradiol receptor or nuclear estradiol receptors and peroxidase activity. The lack of correlation between cytoplasmic estradiol receptors and peroxidase activity is not likely to be due to inhibition of estrogen-inducible peroxidase by endogenous progesterone or the presence of nuclear estradiol receptors in the absence of cytoplasmic receptors. It is concluded that peroxidase activity is not a specific marker for a functional cytoplasmic estradiol receptor in human mammary carcinomas.